Heating apparatus



June 23, 1953 w. HODGINS HEATING APPARATUS Inventoi- Filed May 20, 1949 S N M H M I L w Patented June 23, 1953 HEATING APPARATUS William Hodgins, Ottawa, Ontario, Canada Application May 20, 1949, Serial No. 94,283

1 Claim. (Cl. 236-10) This invention relates to improvements in a heating apparatus andappertains particularly to a circulation control for a forced draft Warm air furnace.

An object of the invention is toprovide a simple, mechanically operated, circulation controlling damper in conjunction with a constantly driven fan, whereby the mass of air in a house or other building is caused to circulate continually but the volume of air being passed through the system is closely related to the furnace heat.

The usual practice in blower-circulated warm air systems of the blower fan coming on intermittently and sometimes remaining off for a considerable period has been found unsatisfactory since the heated air in the rooms on cooling inclines to stratify into horizontal layers of progressively higher temperatures from floor to ceiling so that the least heat remains at the lower levels where the most is wanted and be cause when the blower resumes operation after a period of idleness it delivers for a time a blast of uncomfortably cold air that has been collecting in the ducts and on the floors. To overcome these conditions known to the trade as the cold '70s, the continuous operation of the blower fan has been adopted in some cases and while this eliminates the stratification and intermittent blasts of cold air and tends to maintain a cornmon temperature throughout, it is neither comfortable nor satisfactory, wherethe furnace heat is not constant, once the temperature of the air leaving the furnace goes below 80.

For these reasons it. has seemed desirable to operate the circulating fan continually to avoid stratification and to maintain a common temperature throughout the building but also to re duce the rate of circulation when the furnace temperature lowers and increase the rate of cirl culation when the furnace temperature rises. I have found the simplest and most efficient way of doing this is to locate a damper in the socalled cold air duct leading to the blower fan and to actuate it by means of a thermostat in the hot air duct or plenum leading from the furnace. To thus control the rate of circulation does not disturb the distribution of the heated air in any Way, as occurs'when dampers are introduced into the warm air supply ducts, and further enables the employment of a compact. reliable and easily installed control mechanism.

A further object of this invention is to provide a continuous circulation warm air heating system with a generally improved thermostat-actuated, circulation rate-controlling damper of simple design and economical structure.

A further object of the invention is to provide" such a thermostat-actuated, circulation rate-l controlling damper whose spaced parts are connected by a novel, universa1-type adjustable' linkage. a To the accomplishment of these and related objectsas shall become apparent as the descripbe more clearly described when reference is had to the drawings forming a part of this dis-1 closure wherein like characters indicate like parts 1 throughout the several views.

In the drawings: Figure 1 is a front elevation of a conventional type of forced circulation warm air furnace; Figure 2 is a fragmentary plan thereof;

Figure 3 is a vertical section on the line 3- -3 of Figure 2, looking in the direction indicated by the arrows;

Figure 4 is an enlarged transverse sectional. detail of the thermostat and actuating arm, as]

taken on line 44 of Figure 1; and

Figure 5 is a perspective view of the, adjustable linkage between the thermostat and damper.

The illustrated warm air furnace l is of the cabinet type with a transverse vertical partition 2 dividing the same into separate chambers or compartments 3 and 4 and a heat exchange device '5 in the compartment 3 on one side of the partition and a motor-driven blower fan 6 in.

the compartment 4 on the other side and de:

livering through the bottom of the partition into the first mentioned chamber 3 occupied by the heat exchange device 5.

Two stacks or ducts I and 8 rise from, the top I, communicating reof the furnace cabinet spectively with. the heat exchange device compartment 3 and the blower fan compartment 4.

In use, cold air is drawn down the duct 8 into.

the compartment 4, passed by the fan 8 through the partition 2 in the chamber 3 where it is heated and driven out the warm air duct or (not to one another and longitudinally separated as" will be clearly seen in Figures 1, 2 and 3.

OFFICE These stacks or ducts i and 5, it willj A butterfly damper 9 is positioned in the cold air duct 8, being secured to and balanced on an axis rod 10 pivotally mounted in the front and back walls of the duct, the forward end of the rod terminating exteriorly of the duct. This damper is accordingly long and narrow and easily balanced on the elongated rod joined along its longitudinal medium. It is preferably made narrower than the duct to leave a small clearance along opposite edges when in horizontal position so that it cannot bind on the walls of the stack nor can the duct be ever completely closed there-,

by. It serves then to limit or regulate but can never entirely stop the circulation of air through" the furnace.

In the warm air plenum I, I' mount a heat-responsive device such as a bimetal thermostatll, comprising a mounting sleeve 12 with an which it can' be installed in so many standard arcuately slotted flange 13 on the forward end by which it is adjustably aflixed to the front wall of the stack 1, extending inwards, in parallel relation with the damper axis rod 10, and from which a bimetal helix [4 continues in axial alignment with its adjacent end anchoring to said sleeve I 2 that serves as a radiation shield and its remote or inner end attaching to an axis shaft 15 that extends forwards through the radiation sleeve I 2 and projects beyond the flange thereof exterior of the warm air plenum or stack 1.

A radiall extending lever arm [6 is nonrotatably applied on the exposed forward end of this shaft I5 as by squaring the end thereof as at I! and securing the parts in assembly by a split pin I8. The flanged mounting sleeve l2 being rotatably adjustable on the outside of the front of the stack 1 enables the-initial setting of the shaft l5 as desired.

A companion and relatively parallel lever arm 19 is similarly mounted on the exposed forward end of the damper rod 10 and the free outer ends of these companion lever arms [6 and H! are connected by a universal-type linkage comprising a slidingly adjustable pair of overlapped longitudinally slotted metal straps 20 and 2! releasably secured by fasteners 22 and each perforated at its remote or outer end to pivotally connect With the free outer ends ofthe said radial lever arms I6 and I9 respectively. The damper axis rod lever arm 19 is shown as having a pointer 23 for which graduated orgauge markings 24 may be provided on the cold air stack 8 to facilitate setting and/or adjusting the bimetal control device or the linkage. Additionally a stop 25 is also mounted on the stack 8 to limit the travel of the lever arm l9 so that it may. never attain a horizontal dead-center position.

that might prevent the heat responsive control unit from returning the damper to its "closed.

position or more properly its point of greatest resistance to the intake flow of air. 4

In use, the butterfly damper 9 is set at its point of greatest restriction to the air flow when the temperature in the warm air plenum I is approximately 85 F. and preferably operates through a range to bring it to its point of least resistance to the air flow when the, warm air plenum temperature reaches approximately 175,? F. at about which level the furnace controls,

models of both new furnaces and those presently in use, together with its absence of operating cost and the remoteness of the possibility it will require repair,"adjustment or replacement during the life of the furnace render it highly desirable.

From the foregoing description taken in connection with the accompanying drawings, it will be mainfest that a heating apparatus is provided that'will fulfil all the necessary requirements of such a device, but as many changes could be made in the above description and many apparently widely different embodiments of the invention may be constructed within the scope of the appended claim, without departing from the spirit or scope thereof, it is intended that all matters contained in the said accompanying specification and drawings shall be interpreted as illustrative and not in a limitative or restrictive sense.

Having thus described my invention, what I claim as new and desire to secure b Letters Patent is:

A thermostatically controlled damper structure,

for a forced circulation warm air furnace or the like, comprising in combination with the furnace, a butterfly damper balanced on and secured to a longitudinally extending axis rod; a thermostat spaced from said damper and having a rotatably adjustable sleeve with a flange at one end thereof with spaced arcuate slots extending through said flange, releasable fastening means projecting through said slots and securely attaching said thermostat sleeve to said furnace in rotatably adjustable position, a coaxial shaft journalled in said sleeve and projecting through the flanged end thereof, and a bimetal helix surrounding said shaft and affixed at opposite ends.

to said sleeve and shaft respectively, said shaft being disposed parallel to said damper axis rod:-

a radial arm on said damper rod and another radial arm on said thermostat shaft; and linkage joining saidradial arms comprising a slidably adjustable pair of overlapped longitudinally slotted metal straps releasably secured together by fasteners passing through the slots thereof, and pivotally connected at its outer ends to said re-' spective radial arms.

WILLIAM HODGINS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,770,339 v Lake July 8, 1930 2,007,486 Tretheway July 9, 1935. 2,035,974 McWilliams Mar. 31,- 1936 2,102,873 Anderson Dec. 21, 1937 2,224,210 Anderson Dec. 10, 1940 2,284,674 Murdock June 2, 1942 2,454,044 Eggert Nov. 16, 1948 2,465,151 Dresen "Mar. 22, 19 49 

